The effect of unilateral castration on plasma and testicular testosterone in rabbits from birth to 60 days.

Male rabbits were hemigonadectomized every 10 days from 1 to 50 days of age and were sacrificed 10 days after the operation. Non-operated controls were sacrificed at the same stages. Plasma and testicular testosterone were quantified by radioimmunoassay. Compensatory testicular hypertrophy was not observed in hemicastrated rabbits. Hemicastration has variable effects on testicular and plasma testosterone levels as a function of age. When it is performed at birth, there is a significant increase in testicular and plasma concentrations of testosterone. Similar results are obtained if the operation is performed at 30 days. Unilateral castration performed at 10, 20 and 50 days reduces testicular and plasma testosterone levels. When hemicastration is performed at 40 days or at the adult age, testicular and plasma testosterone levels are not modified.